docs: def add_xml_to_node(self, node):
          """
          For exporting, set data on `node` from ourselves.
          """
          # pylint: disable=E1101
          # Set node.tag based on our class name.
          node.tag = self.xml_element_name()
          node.set('xblock-family', self.entry_point)
  
          # Set node attributes based on our fields.
          for field_name, field in self.fields.items():
              if field_name in ('children', 'parent', 'content'):
                  continue
              if field.is_set_on(self) or field.force_export:
                  self._add_field(node, field_name, field)
  
          # A content field becomes text content.
          text = self.xml_text_content()
          if text is not None:
              node.text = text